Gun Review: Brethren Armament BA 9mm Compact Pistol (MP5K)

The MP5 was the apex predator of its day. Here on the 50th anniversary of the very first production run military and law enforcement organizations around the globe continue to deploy the gun. That said, the firearms world has moved on. New production versions of the MP5 are stamped on old worn-out machines in various countries with abundant QC issues. Taking a different tack, Brethren Armament set out to resurrect the MP5 in all its glory . . .

I’ve reviewed my fair share of MP5 variants. I’ve had the pleasure of playing with an original German MP5K PDW. I’ve reviewed the Turkish Z-5P version. While I haven’t had enough time with the Pakistani POF MP5 to write a full review, we’re well acquainted. And every time I encounter an MP5 from one of these overseas factories, the first thing that I notice is their fit and finish.

The original MP5K PDW is a thing of beauty, from the precision and craftsmanship of the welds on the stamped receiver, to the feel of the external coating as you run your finger along the ridges. A proper MP5K finish should feel like a well oiled supermodel — POF’s gun doesn’t feel that way. At all. Zenith’s version comes close. But Brethren’s all-American-made version makes the grade.

Check out the weld line along the bottom of the rear sight assembly of the Brethren Armament gun (or BA9C). On the imported guns that bead looks clunky and haphazard, with imperfections in both position and quality. On the BA9C, the weld is smooth and consistent, created in one clean pass by a competent craftsman.

It’s not just a question of aesthetics. You don’t just buy a BMW for performance; you buy it for the way it looks and feels. If it was simply a matter of bang for the buck, you’d buy a Subaru Impreza Turbo. The ballistic versions of the Beamer and Scooby have their places in the firearms world (Lord knows I own a few from each end of the spectrum). But when you’re spending this kind of money you don’t want good enough. You want perfect.

Another area where the BA9C’s quality manufacture is evident: the muzzle’s three-lug adapter. As with a standard MP5K, you can remove the Brethren’s three-lug adapter’s thread protector and slip on any silencer that’s threaded in the standard 1/2×28 thread pitch. If you’re in a hurry, you can pop on any can with the common three-lug H&K adapter. With the Turkish firearms I tested the three-lug adapter was noticeably out of spec. The BA9C’s three-lug adapter is spot-on. Given that most adapters are built for the looser tolerances common to modern MP5s this isn’t a huge issue, but I know I feel better when I slot on my thousand dollar silencer that the mount was built right and won’t cause any baffle strikes.

Brethren Armament achieves this level of quality because it produces the BA9C in the U.S. from the MP5’s original specs, using brand new stamping equipment. Closely monitoring the quality of the product coming off the line, using trusted manufacturers for the parts they can’t make in-house, Brethren’s firearm is 100 percent 922(R) compliant [Note: as no parts are imported, the regulation doesn’t apply.] and a thing of mechanical beauty.

Not to belabor the point, Brethren recently proved its dedication to quality when they discovered a third party shop’s parts weren’t up to snuff. Instead of shipping the guns as-is, they stopped production. They are working to bring the production of those parts in-house so they can control the quality, and in the meantime they are offering refunds on any pre-orders who don’t want to wait for the finished product.

The MP5 is made from stamped metal welded into place. The original design was crafted so owners could clamp accessories to the top of the receiver — things like the B&T Picatinny clamp or the H&K scope claw mount. The problem with this setup: there’s an extra bit of engineering between the receiver and the optic, something that can wiggle loose during extreme use that also adds to the overall height of the gun.

BA’s solution: weld a custom Picatinny rail directly to the top of the receiver. This provides the smallest overall profile for the firearm and allows an optimal co-witness between the iron sights and a red dot (like the Aimpoint above). It also increases the firearm’s rigidity and structural stability. The MP5K design already calls for a couple strengthening plates at the rear of the firearm. Brethren’s modification adds an additional strengthening point, which is a good thing indeed.

With two exceptions — the welded rail on top and the custom trigger pack which keeps users from dropping in a full-auto pack, making an illegal machine gun — the BA9C is otherwise 100 percent compatible with existing MP5K parts. The SB Tactical pistol arm brace for the MP5K, for example, fits with ease. Silencers (both 3-lug and 1/2×28 varieties) are completely compatible. And magazines of all shapes and sizes are good to go.

Out on the range the gun performs like the thoroughbred she is. The BA9C’s standard MP5 trigger is a little on the squishy side for my taste, but it’s hardly a thrill killer. I ran through 200 rounds just chucking lead at dirt clods before I could get myself to focus on anything more precise. Add a silencer like this Liberty Suppressors Mystic-X and you’ve got yourself an amazing firearm for some quiet fun. Add a stock and it’s an ideal gun for new shooters.

Standing at 30 feet and using the Aimpoint red dot I was able to slide five rounds into the ragged hole you see before you. It was just a little north of an inch wide, but good enough for shooting whatever needs to be shot. From plate racks in a 3-gun competition (trooper division, for example) to just pinging steel in your backyard, the BA9C doesn’t disappoint.

Brethren Armament has knocked this one out of the proverbial park. They’ve brought sexy back, MP5 style. There’s no doubt that Brethren makes the finest example of the legendary gun available on the market today. Priced within $200 of its imported competition, this is the one to have.

Wow. Reading through these comments just makes me want to grab a motherfucker by the throat. Half you idiots wouldn’t know an mp5 from a whole in the ground. 10% of you apparently want a job with ATF and most of the rest are a bunch of fucktards who are jealous.

This has become a forum for people to complain about what they cant afford. If its over someones budget, then its automatically a shit gun thats outdated and overpriced. In all honesty 1500-2000 isnt that bad for a exact clone of an MP5 that you can use HK parts in. And Nick is a dipshit. He gives this 5 stars, but the MKE gets 3. When in reality the ONLY difference is the welds might be a little cleaner on this(which has nothing to do with the function or feel of the gun). Thats it. And to be honest i saw no real difference on the ones i handled in the welding. I have also shot all 3 of these (MKE, MP5 and BA9mm) and there is no real differences in any of the 3. So for this moron to give this a rave review and the MKE a 3 star review just shows you how ignorant he is. And even if a 3 lug barrel was off by a minuscule amount, its something that can be fixed rather easily and adjusted. My hunch is if this was also made in Turkey he would give it 3 stars also. But this is made in the USA, so it gets 5 stars. Thats sort of how Nick is. He also will give a gun 5 stars, then in another review will bash that same gun he gave glowing reviews when comparing it to the gun hes currently reviewing. He is a walking contradiction and anything he writes should be taken as nothing more than amusing reading. And he has NO education on ATF rules and regulations. He shouldnt be writing reviews for a website at all.

The weight really puts things into perspective. 5.5lbs is only a little less than a competently built 5.56×45 SBR. (A DD MK18 weighs in at 5.88 lbs) Ammo weighs about the same, and I am hard pressed to think of a situation where I would trade down to a pistol caliber given those constraints. Looks like the MP5 design is finally obsolete.

Oh there’s no doubt whatsoever that the design is obsolete. I’d take a B&T APC9 over this any day if I were going to actually need to use it. But like I said, with the MP5 these days it’s more about enjoying the experience and the design than finding the leanest and meanest fighting machine available.

So what exactly makes this weapon obsolete? Since your such an expert. The fact it has a non reciprocating charging handle? That it uses sheet metal? So do AK’s, they arent obsolete. If it is so obsolete then why is this still the number 1 used SMG platform in the world? If its so old and outdated, then why do the Navy Seals, SOCOM, Secret Service and FBI still use this weapon? Why do a majority of SWAT teams, even when they have the option of cheaper SMG’s like the Kriss Vector, P90 or even the UMP, still use the MP5? The roller lock system has been proven to be super reliable and durable. The gun still has great ergos and controls, is smooth as silk, is as accurate inside of 50 yards as a laser beam. Again, if this gun were that “obsolete” it would be pretty much be gone from law enforcement and military. Just because it is an almost 60 year old design doesnt mean it is obsolete at all. Many of the same principles and specs that were used in guns in the early 1900’s are still in use today. And are copied by many new designs as well. Just because you prefer a newer platform, doesnt mean this one is obsolete. Many others prefer this over other options.

It has become painfully obvious, in reading your reviews in particular, that you do not know what your talking about. Your a walking contradiction. You say its outdated, yet its a 5 star gun? Would you also give a Musket a 5 star rating? If its obsolete as you say, then its not a 5 star gun. Your full of shit

Your a great talker Nick. Why dont you go sell cars or something. Thats a great business for bullshitters and people who spout out false info. You would do well. Your little anecdotes and quips would really work well in car sales.

Not living in a suppressor friendly state, sub-sonic is not a major issue for me. (I consider it a handgun application in any case.) In my professional experience with firearms, we were not allowed NEAR any suppressors, much less shot with them.

I was talking about professional / socialwork applications. My personal rig comes in at 65 lbs with all gear. When I put it on after a decade of swivel chair work, I got a brand new appreciation for the importance of daily PT. When you consider that the whole point of subguns was to provide a lighter and quicker handling platform, modern advantages in intermediate cartridge carbines have more or less made the entire category practically obsolete.

They served a purpose back when your other option was a FN FAL, G3, or an M14, but these days, I put them in the same category as turret rifles. Cool, fun to shoot, but functionally useless.

5.8″ barreled 5.56 makes about as much sense as a sawed off JFrame. The whole “how short can you go” with the AR design, stopped making much sense at 16. Stopped making any sense at all at 14.5, at 11 went full ‘tard, and beyond that became little more than a silly exercise in inducing hearing damage, while lobbing .22s at .22 velocities and ruining silencers.

That being said, improvements in accuracy of manufacture of both guns and ammo, as well as vastly improved optics, are crying out for an 8″ (or 7″-9″) carbine, in .357 Sig. Brethren should make an MP5 patterned one. It will be a really useful weapon, with currently few equals. Vaunted .357 mag terminals up close, currently “good enough for Hoover’s boys” 9mm at 100-150 yards. With accuracy at that range similar to a service auto at 25.

Doesn’t have 62 gr (like M855), but shooting 55 gr rounds (like M193), a 14″ barrel loses less than 4% energy compared to 18″, and 10″ is about a 12% loss. They didn’t have a 20″ barrel, but I’m pretty sure the difference between 18 & 20 is minimal (Crane Mk12 DMR had an 18″ barrel).

You have to get all the way down to a 4″ barrel to drop anywhere near 22LR velocities.

Tactically speaking, you’re correct. An short barreled AR more sense if you kick down doors for a living. But I’m not, nor will I ever be, an operator.

I love my AR, but it has some serious logistical drawbacks for me. For starters, I can’t practice with it at the local indoor range (well, I can, but I have to buy their frangible ammo, which costs $1 a round), and the closest place I can shoot it is nearly an hour and a half away. Plus, .223/5.56 ammo is roughly twice the price of 9mm, and my steel targets aren’t rated for it unless they’re out past 100 yards.

I thought about building a 9mm AR to practice with (given the scarcity of .22 LR, I don’t want to go that route, at least not yet), but when I priced out the parts I wanted (same furniture, sights, charging handle, etc. as my primary AR), it was only a couple hundred bucks less than the offerings from Brethren Armament. Sure, it would allow me to practice my rifle shooting techniques on the cheap, much closer to my house, while maintaining the same manual of arms… but the MP5 is just so damn cool. This review sealed the deal for me.

This is irrelevant to guns but as a diehard Porsche fan i have to say you DO buy a Porsche for the performance. The original idea behind the brand is performance, affordable. The 3 cashcow models aside (necessary evils), the idea of 911 being a luxury car would make Herr Porsche turn in his grave. Cayman for the win. Or 918 if you got the money. For the price of a new 991 I’d buy some other GT for luxury or a second hand 430 for performance. They are just reluctant to change the brand icon from an RR to an MR. Such a shame that the Cayman gets forced into lower specs. And now with 2 cylinders cut away it gets even worse.

If you buy a Porsche for the performance nowadays you’re doing it wrong. My STi will eat all but the highest end models for lunch, and for the amount of money it takes to get those models you could simply put money into the STi and have enough left over for a used honda civic on off days.

My dad’s base model 911 was always slower than my car, but I got looks from people while driving it that would not have even seen my STi.

I never ever respected the 911 in any other way than “it was the beginning”. That’s it. It needs to go. But sadly i know it wont.
As for the STi, well, I’m an EVO guy for that matter… Got hooked by EVO8. I’ve test driven the STi years ago, dunno what model it was, but never really got to know it well

And you are right about 911 not being fast enough.
They try to make the 911 into the image of a luxury GT yet they only have a tiny engine compartment to work with and they are unwilling to give up on the racing pedigree they have. It’s a halfassed job to say the least.
And they refuse to acknowledge the potential of the MR platform for speed.
Meh, it just sucks either way.
Hate to see my fav brand with so much capability only having a 918 as a decent representation, which is out of the reach of almost everyone.

I’m genuinely curious here: is having a factory SBR really that important? The current pistol version can be Form 1’ed easily, and once you have the stamp back you just pop a stock on it and you’re good to go. It’s compatible with all existing MP5K stocks so that’s only about a $250 change.

You have to engrave your own info on if you’re doing a form 1 build. Do you want the Porsche built by Porsche, or the one built by Porsche and “CWM Trust, Bumscrew, ID”? Huge difference with resale value.

Are you really going to try to sell an NFA item? One that can’t be converted back to an easy to sell non-nfa configuration like an AR? With months of waiting for another tax stamp for the new owner who won’t be able to touch it in the meantime?

I get that this is true to the MP5k’s original design, but the presence of these “pistols” on the market only strengthens my desire to see the NFA repealed. In an ideal world, I could have one of these shipped to my doorstep in a neat little briefcase; firearm and three mags in the bottom foam panel, A2 and A3 stocks in the top.

Not to mention that ‘arm braces’ and the fact that any criminal, should they want to, could buy a pistol upper and attach it to a rifle lower, or saw off a shotgun without a care in the world (Yet they don’t seem to do this, or they only have them for status reasons, because they seem to never actually be used in real crimes) makes it clear that the NFA is simply obsolete and ineffective (as it was from day 1) in actually being effective at doing anything but being an enormous pain in the ass for the law-abiding.

The AK-47 was designed to be made as cheaply and quickly as possible. The Tavor is mostly injection molded plastic with some parts specifically designed to be made on modern machines quickly. The AR-15 is mass produced at such a volume that the price has been greatly reduced.

This is a gun designed to be built on stamping machines and hand worked on lathes, not by the CNC machines we have these days. The manufacturing process takes longer, and the fact that very few people make MP5s means that the parts are more scarce and expensive.

Michael, we understand the questioning of wanting to know why a sheet metal gun is $1900.
The parts themselves, bolt, carrier, trigger pack are the largest part of the expense.
But good news, WE are working on reducing these costs over the next 60-90 days.

From a technical standpoint, the MPX is arguably superior, but I don’t operate operationally, and thus, such things can be (and often are) less important than the cool factor. Don’t get me wrong. The MPX is cool as hell. But, it will NEVER be MP5 cool.

Did you know that H&K introduced a MP5 semi auto only carbine/pistol on this years IWA hear in Germany? They will sell that at least to the German civilian market, but I have no idea if you could buy them in the States, because of import and export laws. The gun will be called SP5k, because of German laws.
Her a video firing the thing:

There are certain firearms which are banned from importation into the United States for civilians by name. I’m pretty sure the HK MP5 is one of those guns — the way that Zenith and POF get around this is by naming them a different model name. Same way that the HK “sporting rifles” made it into the country.

Could HK change the name and get around that block? Possibly. But for now, this is the best that is available.

Ahem. That’s like saying “The fox was the apex predator of its day.” I mean there are smaller predators, but wolves, bears, tigers and lions would like to say hello. Like every center fire military rifle ever would like to say to the MP5.

Meanwhile, semiauto versions of full auto machine pistols aren’t sexy, they’re kind of silly. Like dressing up your corgi in a fox costume and calling it an “apex predator.” It’s just a big, chunky 9mm pistol, guy. Don’t people make fun of High Point 9mms for being big and chunky?

Quinn McIntosh took $1000 down on an AR about a year ago. I have not received a gun. He will not take or return my phone calls or respond to my emails. I guess he just want to keep my thousand dollars without giving me anything in return. I guess he hopes that I will just go away. Am I the only person he is trying to rob?